https://fontawesome.com/v4.7.1/icons/ code example
Example: font awesome css
<span style="font-size: 3em; color: Tomato;">
<i class="fas fa-camera"></i>
</span>
<span style="font-size: 48px; color: Dodgerblue;">
<i class="fas fa-camera"></i>
</span>
<span style="font-size: 3rem;">
<span style="color: Mediumslateblue;">
<i class="fas fa-camera"></i>
</span>
</span>